Hot/cold press forming methods for shaping thermoformable materials

ABSTRACT

One method of forming a workpiece made of thermoformable material includes the steps of: (a) supporting a raw workpiece on a suspension tray; (b) moving a pair of relatively hot forming dies into position above the workpiece; (c) closing the hot forming dies against the workpiece to heat the workpiece and to form and shape the workpiece into the desired configuration; (d) opening the hot forming dies and removing the hot forming dies away from the workpiece; (e) moving a pair of relatively cold forming dies into position above and below the workpiece; (f) closing the cold forming dies against the workpiece to cool the workpiece while maintaining the workpiece in the desired configuration; and, (g) opening the cold forming dies and removing the finished workpiece form the suspension tray. Other methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of copending application Ser. No.07/233,639, filed Aug 18, 1988 entitled "Hot/Cold Press Forming Methodsand Apparatus for Thermoformable Materials" now U.S. Pat. No. 4,948,355mgranted Aug. 14, 1990. Application Ser. No. 07/233,639 is acontinuation-in-part of application Ser. No. 07/052,622, filed May 20,1987 entitled "Hot/Cold Press Forming Methods and Apparatus forThermoformable Plastic Materials", now U.S. Pat. No. 4,789,328, grantedDec. 6, 1988. Application Ser. No. 07/052,622 is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1) Field of the Invention

My invention is in the field of apparatus and methods for forming andshaping a workpiece made of thermoformable material. The broad term"thermoformable material" is defined to include any material thatbecomes formable when heat and pressure are applied. For example,apparatus and methods for forming and shaping a workpiece made ofthermoformable metal materials, such as superplastically-formablealloys, titanium, and titanium alloys, are within the field of myinvention. Further examples are apparatus and methods for forming andshaping a workpiece made of materials which contain thermoplastic resinsand thermosetting resins. Thermoplastic resins are defined as materialswhich have the property of softening or fusing when heated and ofhardening and becoming rigid again when cooled. Thermosetting resins aredefined as materials which have the property of becoming permanentlyhard and rigid when heated to a critical temperature.

One important type of thermoplastic material is thermoplastic compositematerial. Thermoplastic composite materials are combinations of athermoplastic resin and another material differing in composition orform. The constituents retain their physical identities in the compositematerial, that is, they do not dissolve or otherwise merge completelyinto each other although they act together. Advanced composite materialsare composite materials made by embedding high-strength, high-modulusfibers within an essentially homogeneous matrix. In one particularexample, the invention relates to an apparatus and method for formingand shaping aerospace parts made of advanced thermoplastic compositematerials. Advanced thermoplastic composites are now being employed aslightweight structural materials in many aerospace uses.

2) Description of the Related Art

Currently, press forming or shaping of structural components made ofadvanced thermoplastic composite materials for aerospace use isgenerally accomplished by heating a pre-consolidated sheet or blank ofmaterial in an oven to 750°-800° F. and then transferring it by hand toa press as fast as possible where it is formed between dies before itcools. This process is difficult, cumbersome, and time-consuming. Inmany cases, the blank of material will cool below the meltingtemperature and begin solidification before the dies can be closed.Forming the component in this way will result in damage to the material.Manual handling of the material blanks at elevated temperatures(750°-800°0 F.) requires thick heat-resistant gloves and this makesaccurate positioning of the blank in relation to the dies verydifficult.

There is also a process for consolidating flat sheets of advancedthermoplastic composites that is known in the art. The process involvesstacking thin layers of flat blanks of thermoplastic composite material.The stack of flat sheets is heated by being placed in a press with hotplatens. The hot material is then transferred by hand to another presswith cold platens where the material is pressed flat and held underpressure until cooled. Here again the problem is that the material coolsrapidly while being moved between presses and, if used to form shapedcomponents, accurately positioning the hot blanks relative to the diesby hand would be difficult.

SUMMARY OF THE INVENTION

One method of the present invention begins by supporting a raw workpieceon a suspension tray. Then a pair of relatively hot forming units ismoved into position above the workpiece and below the suspension tray.Next the relatively hot forming units are closed against the workpieceand the suspension tray to heat the workpiece and to form and shape theworkpiece into the desired configuration. In one embodiment, apositioning wheel is used to rotate the workpiece in relation to theforming units while working the workpiece into its final configuration.Then the relatively hot forming units are opened and moved away from theworkpiece and the suspension tray. Next a pair of relatively coldforming units is moved into position above the workpiece and below thesuspension tray. Then the relatively cold forming units are closedagainst the workpiece and the suspension tray to cool the workpiecewhile maintaining the workpiece in the desired configuration. Finally,the relatively cold forming units are opened and the finished workpieceis removed from the suspension tray.

One apparatus of the present invention includes: (a) a base member; (b)a positioning frame supported by the base member; (c) a suspension trayfor supporting a raw workpiece, the suspension tray being supported bythe positioning frame; (d) a first pair of forming units supported bythe base member; (e) a press platen; (f) a second pair of forming unitsmoved by the press platen; (g) an actuator for moving the suspensiontray whereby the suspension tray may be moved to a first position and toa second position between the pairs of forming units; and (h) a cylinderfor moving the press platen whereby the first pair of forming units andthe second pair of forming units may be closed against the raw workpieceand the suspension tray.

Platen and consequent forming unit alignment may be accomplished byusing conventional press tie rods which structurally tie together thepress headframe and the base platen. However, conventional tie rods arenot considered essential because forming unit alignment may beaccomplished in a variety of ways. Moreover, a variety of press designscan employ the foregoing inventive combination of a pair of relativelyhot forming units and a pair of relatively cold forming units in asingle press apparatus.

The present invention solves the previously existing problems in thefollowing way. By placing the raw workpiece material on a suspensiontray, the workpiece can be positioned on a low temperature member thatcan be rotated mechanically in relation to the forming units. If needed,a cover sheet or film may be placed on top of the workpiece to preventsticking to the upper hot forming unit. The motion of the suspensiontray relative to the relatively hot forming units can be sequenced andprogrammed to form one area before another area, similar to handworking. In other cases, pre-plied stack ups can be formed andconsolidated in finished parts saving the expense of putting thematerial into pre-consolidated sheet form. Heat is transferred into theraw workpiece by radiation and/or convection by a slow clamping motion.This method enables the press operator to do all of the handling of thematerial when it is at a low temperature and solidified, therebyeliminating the problems of handling a hot limber material when workingthermoplastics. The forming units can be moved in and out rapidlywithout the workpiece being thrown off or out of position because theworkpiece stays on the suspension tray in the center of the press. Byusing both a relatively hot pair and a relatively cold pair of formingunits, the process of heating, forming, and cooling the work materialcan be speeded up significantly especially when the workpiece is anadvanced thermoplastic composite material which has to be heated to therelatively high temperature of approximately 750° F. Heating a pair offorming units to this temperature and then cooling the same pair offorming units again to room temperature could take several hours. Usingseparate pairs of forming units for heating and cooling enables theheating and cooling process to be accomplished in a matter of minutes.

Another advantage of the present invention is that high cost diefinishing is not always required because the suspension tray and thecover sheet (if used) contact the workpiece and in doing so impart theirfinish on the workpiece. In this manner, a variety of textures andfinishes can be molded by changing the cover sheet and suspension trayfinish rather than the die.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a first embodiment of a hot/cold pressforming apparatus constructed according to the principles of the presentinvention. The press platen and its actuating cylinder and rod are shownin phantom. Conventional press tie rods, which may be employed, are notshown in these drawings.

FIG. 2 is a front elevational view of the inventive apparatus of FIG. 1showing the apparatus in the material load/unload position.

FIG. 3 is a partial vertical sectional view taken along line 3--3 inFIG. 2 showing the positioning wheel and the suspension tray with thesuspension tray supporting a raw workpiece. The press platen and thepressure transfer blocks have been omitted for clarity.

FIG. 4 is an isometric view of a finished thermoformable plasticworkpiece having a Z-shape.

FIG. 5 is a front elevational view of the inventive apparatus of FIG. 1showing the right hand pair of dies (the relatively hot dies) inposition above the workpiece and below the suspension tray before pressclosing.

FIG. 6 is a front elevational view of the inventive apparatus of FIG. 1showing the press platen down and the relatively hot dies in the closedposition on the workpiece and the suspension tray.

FIG. 7 is a front elevational view of the inventive apparatus of FIG. 1showing the left hand pair of dies (the relatively cold dies) inposition above the workpiece and below the suspension tray before pressclosing.

FIG. 8 is a front elevational view of the inventive apparatus of FIG. 1showing the press platen down and the relatively cold dies in the closedposition on the workpiece and the suspension tray.

FIG. 9 is a side elevational view of the apparatus of FIG. 5 showing theraw workpiece supported on the suspension tray between the relativelyhot dies with a cover sheet on top of the workpiece to prevent stickingto the upper die. The relatively hot dies are in the open positionbefore press closing. The die mounts are shown in vertical section.

FIG. 10 is a side elevational view of the apparatus of FIG. 6 showingthe workpiece supported on the suspension tray at the point in theforming process when the relatively hot dies are in the fully closedposition and the workpiece has been formed into the desired shape.

FIG. 11 is a side elevational view of the apparatus of FIG. 7 showingthe workpiece supported on the suspension tray between the relativelycold dies. The relatively cold dies are in the open position. The diemounts are shown in vertical section.

FIG. 12 is a side elevational view of the apparatus of FIG. 8 showingthe workpiece supported on the suspension tray between the relativelycold dies which are in the closed position to cool the workpiece.

FIG. 13 is an isometric view of a second embodiment of a hot/cold pressforming apparatus constructed according to the principles of the presentinvention. The press platen and its actuating rod are shown in phantom.

FIG. 14 is a partial vertical sectional view of the apparatus of FIG. 13and shows the positioning posts and the suspension tray with thesuspension tray supporting a raw workpiece. The press platen and thepressure transfer block have been omitted for clarity.

FIG. 15 is an isometric view of a third embodiment of a hot/cold pressforming apparatus constructed according to the principles of the presentinvention. The actuating rod for the press platen is shown in phantom.

FIG. 16 is a front elevational view of the apparatus of FIG. 15 andshows the positioning frame and suspension arms supporting thesuspension tray at a level that gives it clearance for movement abovethe lower dies.

FIG. 17 is an isometric view of another embodiment of a hot/cold pressforming apparatus constructed according to the principles of theinvention.

FIG. 18 is a front elevational view of the apparatus of FIG. 17 andshows the positioning frame and support arms supporting the suspensiontray at a level that gives it clearance for movement above the lowerforming units.

FIG. 19 is an isometric view of a finished thermoformable plasticworkpiece having vertical side walls.

FIG. 20 is a schematic drawing of a front elevational view of anotherembodiment of a hot/cold press forming apparatus constructed accordingto the principles of the invention.

FIG. 21 is a schematic drawing of a front elevational view of anotherembodiment of a hot/cold press forming apparatus constructed accordingto the principles of the invention.

FIG. 22 is a schematic drawing of a front elevational view of anotherembodiment of a hot/cold press forming apparatus constructed accordingto the principles of the invention.

FIG. 23 is an isometric view of another embodiment of a hot/cold pressforming apparatus constructed according to the principles of theinvention.

FIG. 24 is a vertical sectional view of another embodiment of a hot/coldpress forming apparatus constructed according to the principles of theinvention.

FIG. 25 is a vertical sectional view of another embodiment of a hot/coldpress forming apparatus constructed according to the principles of theinvention.

FIG. 26 is a vertical sectional view of another embodiment of a hot/coldpress forming apparatus constructed according to the principles of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, FIGS. 1 and 2 show the first embodiment of ahot/cold press forming apparatus 20 constructed according to theprinciples of the invention. The terms "hot" and "cold" are used in arelative sense to mean that there exists a temperature differentialbetween the two pairs of forming units. Apparatus 20 includes a pressplaten 22 which is vertically actuated by a rod 24. Rod 24 is driven bya conventional double-acting cylinder 25 of either the hydraulic orpneumatic type. Cylinder 25 is mounted on a headframe (not shown) or anon-moving structure above press platen 22. Other conventional pressactivating mechanisms may be employed in lieu of the cylinder.

Platen 22 has mounted on its lower face two pressure transfer blocks 26and 28 in a spaced-apart relationship. Pressure transfer blocks 26 and28 are shown as separate members in the drawings, but they may beconstructed in a variety of other ways such as integral parts of platen22. In the center portion of apparatus 20 is a positioning wheel 30, theupper portion of which is located between pressure transfer blocks 26and 28. As shown in FIG. 3, positioning wheel 30 is circular in shapeand its outer periphery carries teeth 32. Teeth 32 engage gears 34 and36 which support positioning wheel 30. Gears 34 and 36 are mounted onbase platen 38.

Base platen 38 may be omitted from the construction of apparatus 20, inwhich event base member 82 may rest directly on the factory floor and bealigned by other means. Gears 34 and 36 may also be mounted on thefactory floor or be mounted on arms extending out from base member 82.Gear 36 is powered by a reversible motor (not shown), so thatpositioning wheel 30 can be rotated in either direction by programmablecontrols or the press operator.

Positioning wheel 30 has four adjustable suspension arms 40a, 40b, 40c,and 40d mounted inside the wheel. The arms include a section constructedof springs 42a, 42b, 42c, and 42d or of an elastic material. The foursuspension arms each have Y-shaped harnesses which are attached to andsupport a suspension tray 44 located at the center of the wheel 30. Asshown in FIGS. 9 and 11, suspension tray 44 is supported at a level thatgives minimum clearance above the lower dies 50 and 76.

As shown in FIGS. 3 and 9, suspension tray 44 supports raw workpiece 46which is to be formed and shaped by the press. A cover sheet or film 47(FIG. 9) may optionally be used on top of and/or below workpiece 46.Suspension tray 44 is a preformed member, preferably made out of thinsheet metal (such as aluminum alloy or stainless steel), and having ashape which is similar to the forming dies. The term "tray" when usedherein is to be understood as a thin sheet made in a shape generallyconforming to the die pairs. For example, suspension tray 44, upper hotdie 48, and lower hot die 50 may all have a Z-shape in side view asshown in FIG. 9. This is the shape of the finished workpiece 52 as shownin FIG. 4. It is to be understood that the Z-shape is shown by way ofexample only and that a variety of other shapes may be used inpracticing the invention. Suspension tray 44 is shown as a solid memberin the drawings but it may be modified to provide for the application ofa vacuum through the suspension tray to hold the workpiece in place.

As shown in FIG. 9, upper hot die mount 54 and lower hot die mount 68have external insulation boards 55 and 69 to insulate the die mountsfrom the upper hot die 48 and the lower hot die 50, respectively. Upperhot die 48 and lower hot die 50 are heated by heating elements 49 and51, respectively. Dies 48 and 50 each have conventional temperaturegauge and control capabilities such as internal thermocouples (notshown). Upper die mount 54 is attached to the right support arm 58 bymeans of a sliding track 60 as shown in FIG. 1 which has either aspring-driven or a cylinder-driven return so that when platen 22 andpressure transfer blocks 26 and 28 are retracted then upper die mount 54will return to its elevated or open position. The small holes 84 in theside walls of die mounts 54 and 68 are to lighten the weight of the diemounts and to cool them.

Right support arm 58 supports upper hot die mount 54 and is attached tolower hot die mount 68, whereby both move horizontally left and rightwith support arm 58. Lower hot die mount 68 slides horizontally on topof base member 82. A guide or track (not shown) may be used for reducedfriction and better alignment. Lower die mount 68 does not movevertically, whereas upper die mount 54 moves up and down in response toplaten 22 and pressure transfer blocks 26 and 28 when right support arm58 is in the retracted or pressing position (FIGS. 5 and 6). Rightsupport arm 58 is moved horizontally by rod 72 which is driven by adouble-acting cylinder 74 of either the hydraulic or pneumatic typemounted in the right side of base 82 which also supports right supportarm 58.

As shown in FIG. 11, upper cold die mount 62 and lower cold die mount 56have internal cooling elements 63 and 57 for cooling the upper cold die70 and the lower cold die 76, respectively. Dies 70 and 76 each haveconventional temperature gauge and control capabilities such as internalthermocouples (not shown). Upper cold die mount 62 is attached to theleft support arm 64 by means of a sliding track 66 (shown in phantom inFIG. 2) which has either a spring-driven or a cylinder-driven return sothat when platen 22 and pressure transfer blocks 26 and 28 are retractedthen upper die mount 62 will return to its elevated or open position.Small holes 86 in the side walls of die mounts 56 and 62 are to lightenthe weight of the die mounts and to cool them.

Left support arm 64 supports upper cold die mount 62 and is attached tolower cold die mount 56, whereby both move horizontally left and rightwith support arm 64. Lower cold die mount 56 slides horizontally on topof base member 82. A guide or track (not shown) may be used for reducedfriction and better alignment. Lower die mount 56 does not movevertically, whereas upper cold die mount 62 moves up and down inresponse to press platen 22 and pressure transfer blocks 26 and 28 whenleft support arm 64 is in the retracted or pressing position (FIGS. 7and 8). Left support arm 64 is moved horizontally by rod 78 which isdriven by a double-acting cylinder 80 of either the hydraulic orpneumatic type mounted in the left side of base 82 which also supportsleft support arm 64.

Platen alignment, that is, alignment between press platen 22 and baseplaten 38, and consequent die alignment may be accomplished by employingconventional press tie rods which structurally tie together theheadframe (not shown) or some other non-moving structure above pressplaten 22 and the base platen 38. However, conventional tie rods are notconsidered essential because die alignment may be accomplished in otherways. A variety of press designs can employ the foregoing inventioncombination of a pair of relatively hot dies and a pair of relativelycold dies in a single press apparatus.

FIGS. 13 and 14 show the second embodiment of a hot/cold press formingapparatus 90 constructed according to the principles of the invention.Apparatus 90 is a simplified version of the apparatus 20 shown in FIGS.1 and 2. Components of the two embodiments having like design andconstruction have been given the same reference numerals in thedrawings.

The primary difference between the first and second embodiments is thatpositioning wheel 30 has been replaced by two vertical I-shapedpositioning frames 92 and 94 which are mounted on base member 82a. Eachof the four adjustable suspension arms 96a, 96b, 96c, and 96d have oneend attached to one of the positioning frames 92 or 94 and the other endattached to suspension tray 44 located midway between the positioningframes 92 and 94. Platen 22 has mounted on its lower face a singlepressure transfer block 98. Pressure transfer block 98 is shown as aseparate member in FIG. 13, but it may be constructed as an integralpart of platen 22. Also, in this embodiment, cylinders 74 and 80 may becombined into a single double-acting cylinder with a double-end rod. Inother respects, the construction and operation of apparatus 90 is thesame as apparatus 20. It is to be understood that base platen 38 may beomitted from the construction of apparatus 90 in which case base member82 would rest directly on the factory floor.

FIGS. 15 and 16 show the third embodiment of a hot/cold press formingapparatus 100 constructed according to the principles of the invention.Apparatus 100 is designed for forming and shaping larger workpieces madeof thermoformable material which necessitate the use of larger andheavier dies in the press apparatus. Hence, in this embodiment, the diesare horizontally stationary and the suspension tray and workpieces aremoved horizontally from one pair of dies to the other pair of dies. Toprevent uneven loading of the press (which is undesirable), a dummyworkpiece moves into position in the unused pair of dies at the sametime that the real workpiece moves into position in the used pair ofdies.

Apparatus 100 has certain components that are the same as in the firstembodiment apparatus 20 shown in FIGS. 1 and 2. Components of the twoembodiments having like design and construction have been given the samereference numerals in the drawings.

In FIGS. 15 and 16, upper hot die 48a and upper cold die 70a are mountedon the lower face of platen 22. A layer of insulation 102 separatesplaten 22 from dies 48a and 70a. Another layer of insulation 104separates dies 48a and 70a from each other.

Lower hot die 50a and lower cold die 76a are mounted on base member 82b.A layer of insulation 106 separates base member 82b from dies 50a and76a. Another layer of insulation 108 separates dies 50a and 76a fromeach other.

Located on the front side of apparatus 100 is a first positioning frame110 having a horizontal member 111 and two vertical T-shaped positioningposts 112 and 114. Horizontal member 111 slides back and forth on top ofbase member 82b. Each of the four adjustable suspension arms 116a, 116b,116c, and 116d have one end attached to one of the vertical positioningposts 112 and 114 and the other end attached to suspension tray 44a. Asecond positioning frame 118 of like design having a horizontal memberand two vertical T-shaped positioning posts is located on the rear sideof apparatus 100. Four more adjustable suspension arms of like designhave one end attached to one of the vertical positioning posts ofpositioning frame 118 and the other end attached to suspension tray 44a.

Positioning frame 110 is moved back and forth in a horizontal plane byrod 130 which is connected through a linkage to horizontal member 111.Rod 130 is driven by a conventional double-acting cylinder 129 mountedon the front side of base member 82b. A second cylinder and rodcombination of identical design is mounted on the rear side of basemember 82b to move positioning frame 118 back and forth in a horizontalplane in tandem with positioning frame 110 so that suspension tray 44ais maintained in correct alignment with the dies. Alternatively, thecylinders can be mounted on the factory floor or some other non-movingstructure. The positioning frames could also be designed as one piecetied together with cross members, and in that event, one cylinder couldbe employed instead two.

Suspension tray 44a has three work stations 120, 122, and 124. As shownin FIG. 16, a real workpiece 46 is placed on the second work station 122and dummy workpieces 126 and 128 are placed in the first and third workstations 120 and 124, respectively. The dummy workpieces prevent theundesirable situation of uneven loading of the press. When the realworkpiece 46 is being pressed by either the pair of hot dies 48a and 50aor the cold dies 70a and 76a, there is a dummy workpiece of equalthickness being pressed by the other pair of dies.

FIG. 16 also shows that when the dies are in the open positionsuspension tray 44a is held by the suspension arms at a level that givesclearance above the highest portions of lower dies 50a and 76a so thatsuspension tray 44a can move freely back and forth in a horizontal planewithout bumping the lower dies. In other respects, the construction andoperation of apparatus 100 is similar to apparatus 20 described earlier.

The method embodiments of the invention will now be described. Theprocesses begin with the press operator heating the hot dies, such as 48and 50 (FIG. 2) or 48a and 50a (FIG. 15), to the desired temperature.The proper temperature of the hot dies is dependent on the particularthermoformable material that is to be shaped by the apparatus 20 or 90or 100. For example, when raw workpiece 46 is an advanced thermoplasticcomposite material, then the temperature needs to be relatively high.Raw workpiece 46 may be made of the commercially-available advancedthermoplastic composite material known as APC-2 sold by FiberiteCorporation. The APC-2 is supplied as a sheet material which is composedof continuous carbon fibers dispersed in a matrix of PEEK (apolyetheretherketone of repeating units). To form and shape a workpiecemade of APC-2, the hot dies (48 and 50 or 48a and 50a) should be atabout 750° F.

As another example, when raw workpiece 46 is made of thecommercially-available thermoplastic composite material known aspolyphenylene sulfide or PPS, then the hot dies should be at about 650°F.

As a further example, when raw workpiece 46 is made of thecommercially-available thermoplastic composite material known as AZDELsold by PPG Industries Inc., then the hot dies (48 and 50 or 48a and50a) should be at about 450° F. The AZDEL is supplied as a sheetmaterial which is composed of continuous glass fibers dispersed in apolypropylene matrix. Other thermoplastic materials includepolyetherimide and polyethersulfone.

When raw workpiece 46 is made of metal or metal alloy, then thetemperature of the hot dies, such as 48 and 50 or 48a and 50a, should bequite high. For example, when workpiece 46 is made of titanium, then thehot dies should be at about 1400° F.

The next step is for the press operator to coat the upper workingsurface of suspension tray 44 or 44a with a conventional mold releaseagent. The workpiece, when molten, will stick to the suspension tray.When the suspension tray cools down, the finished workpiece will bereleased. The operator coats the suspension tray with mold release agentoccasionally during each run. Cover sheet or film 47 (if used) is alsocoated with mold release agent.

The remaining steps in the method using apparatus 20 or 90 will now bedescribed and following that there will be a description of theremaining steps in the method using apparatus 100. While the apparatus20 or 90 is in the material loading position (as shown in FIG. 2 forapparatus 20), the operator places the raw workpiece 46 on top of thesuspension tray 44 as shown in FIGS. 3 and 9. By using cover sheet 47over the workpiece 46 and other forming aids (such as a second piece ofshaped metal above the workpiece), either preconsolidated sheet materialor ply stack ups of thermoplastic composites may be used. Step formingor bump cycles can be used for shaping complex parts or when usingmaterials with outgassing requirements.

For apparatus 20 and 90, the operator then activates cylinder 74 toretract rod 72 as indicated by the arrow in FIG. 5. This moves rightsupport arm 58 horizontally to the left which brings upper hot die mount54 and lower hot die mount 68 within the plane of positioning wheel 30as shown in FIG. 5. Upper hot die mount 54 is now positioned belowpressure transfer blocks 26 and 28 and above suspension tray 44supporting raw workpiece 46 (FIGS. 5 and 9). Lower hot die mount 68 isnow positioned below suspension tray 44.

The operator then activates cylinder 25 which pushes rod 24 verticallydownward as indicated by the upper arrow in FIG. 6. This downwardmovement of press platen 22 and pressure transfer blocks 26 and 28forces down upper hot die mount 60 and upper hot die 48. Heat istransferred to workpiece 46 by radiation and convection from upper hotdie 48 and lower hot die 50. Upper hot die 48 is lowered slowly until ittouches raw workpiece 46 or cover sheet 47 if used. The operator rotatespositioning wheel 30 as needed so that there is maximum contact and heattransfer from upper hot die 48 to the workpiece 46. Suspension tray 44can move slightly up and down and sideways by virtue of the springs orelastic material in the suspension arms. The slow clamping motion ofupper hot die 48 continues until the hot dies 48 and 50 are fully closedas shown in FIGS. 6 and 10. At this point, the workpiece 46 is beingcompression molded. The amount of pressure applied by the hot dies andthe length of time the compression continues are again dependent on theparticular thermoformable material being employed. With thermoplasticcomposites, the hot dies are kept fully closed and under pressure forthe time period required to completely form and shape the workpiece intothe desired configuration.

The next step is to retract upwardly the press platen 22 and thepressure transfer blocks 26 and 28. Upper hot die mount 54 and upper hotdie 48 return to the open position shown in FIG. 5. Then right supportarm 58 is moved horizontally to the right by extending rod 72. Thismoves the hot dies horizontally to the right and out of the plane ofPositioning wheel 30 and back to the position shown in FIG. 2.

Next the operator activates cylinder 80 to retract rod 78 as indicatedby the arrow in FIG. 7. This moves left support arm 64 horizontally tothe right which brings upper cold die mount 62 and lower cold die mount56 within the plane of positioning wheel 30 as shown in FIG. 7. Uppercold die mount 70 is now positioned below pressure transferred blocks 26and 28 and above suspension tray 44 supporting workpiece 46 (FIGS. 7 and11). Lower cold die mount 56 is now positioned below suspension tray 44.

The operator then activates cylinder 25 which pushes rod 24 verticallydownward as indicated by the upper arrow in FIG. 8. This downwardmovement of press platen 22 and pressure transfer blocks 26 and 28forces down upper cold die mount 62 and upper cold die 70. Upper colddie 70 continues downwardly until the cold dies 70 and 76 are fullyclosed as shown in FIGS. 8 and 12. At this point, the workpiece 46 isbeing compression molded again and simultaneously cooled by the colddies 70 and 76, which may be at room temperature at the beginning. Theamount of pressure applied by the relatively cold dies and the length oftime the compression continues are again dependent on the thermoformablematerial being employed. For example, when the workpiece is made ofAPC-2 the cold dies are held closed and under pressure for the timerequired for the APC-2 to cool to below its glass transition temperaturewhich is about 290° F. As a further example, when the workpiece is madeof polyphenylene sulfide the cold dies are held closed and underpressure for the time required for the polyphenylene sulfide to coolbelow its glass transition temperature of about 180° F. Conventionaltemperature gauge and control capabilities (not shown) are provided tomonitor and maintain the temperature of each cold die.

The next step is to retract upwardly the press platen 22 and thepressure transfer blocks 26 and 28. Upper cold die mount 62 and uppercold die 70 return to the open position shown in FIG. 7. Then leftsupport arm 64 is moved horizontally to the left by extending rod 78.This moves the cold dies horizontally to the left and out of the planeof positioning wheel 30 and back to the position shown in FIG. 2. Theforegoing processing may also be accomplished automatically by usingprogrammable controls.

The operator then unloads the finished workpiece 52 (FIG. 4) fromsuspension tray 44. The process is then repeated on another rawworkpiece 46 as described above.

The remaining steps in the method of using apparatus 100 will now bedescribed. The operator activates cylinder 25 which pushes rod 24vertically downward. This downward movement of press platen 22 forcesdown the upper dies (upper hot die 48a and upper cold 70a). Heat istransferred to workpiece 46 in the second workstation 122 (FIG. 16) byradiation and convection from upper hot die 48a and lower hot die 50a.Upper hot die 48a is lowered slowly until it touches raw workpiece 46(or cover sheet 47 if used). Suspension tray 44a moves down with theupper dies by virtue of the springs or elastic material in thesuspension arms. The slow clamping motion of upper hot die 48a continuesuntil the hot dies 48a and 50a are closed. At this point, the workpiece46 is being compression molded. The amount of pressure applied by thehot dies and the length of time the compression continues are againdependent on the particular thermoformable material being employed. Thehot dies are kept closed and under pressure for the time period requiredto completely form and shape the workpiece into the desiredconfiguration.

The next step is to retract upwardly the press platen 22. The upper diesreturn to the open position shown in FIG. 16. Then positioning frames110 and 118 are moved horizontally to the left by retracting rod 130into cylinder 129 and likewise for the corresponding cylinder and rod onthe rear side. This moves suspension tray 44a horizontally to the leftand locates workstation 122 and workpiece 46 between upper cold die 70aand lower cold die 76a.

The operator then activates cylinder 25 which pushes rod 24 verticallydownward. This downward movement of press platen 22 forces down uppercold die 70a. Upper cold die 70a continues downwardly until the colddies 70a and 76a are closed. At this point, the workpiece 46 is againbeing compression molded and simultaneously cooled by the cold dies 70aand 76a. The amount of pressure applied by the cold dies and the lengthof time the compression continues are again dependent on thethermoformable material being employed.

The next step is to retract upwardly the press platen 22. The upper diesreturn to the open position. The operator then unloads the finishedworkpiece 52 (FIG. 4) from suspension tray 44a. The process is thenrepeated on another raw workpiece 46 as described above.

A variation of the foregoing processes is usually required when the rawworkpiece 46 is made of a thermosetting material. One example of athermosetting material is the commercially-available thermosettingcomposite material which contains a polyimide resin known as PMR-15.

The following description is presented to exemplify the process forthermosetting materials, such as PMR-15, when using apparatus 20 or 90.The process is similar when using apparatus 100. A raw workpiece 46 madeof PMR-15 composite should be pre-heated in an oven to a temperature ofabout 100°-150° F. The operator then transfers the workpiece 46 to thesuspension tray 44 while the apparatus 20 or 90 is in the materialloading position (as shown in FIG. 2 for apparatus 20). In this case,the cooler dies 70 and 76 additionally have heating elements which areused to pre-heat dies 70 and 76 to an intermediate temperature of about430° F. The cooler dies 70 and 76 are then brought into position aboveand below the workpiece 46 by moving left support arm 64 horizontally tothe right by activating cylinder 80 to retract rod 78 as indicated bythe arrow in FIG. 7.

The operator activates cylinder 25 which pushes rod 24 verticallydownward. The downward movement of press platen 22 forces cooler die 70downward until cooler dies 70 and 76 are closed as shown in FIGS. 8 and12. The workpiece 46 is thus heated to about 430° F. and compressionmolded by dies 70 and 76. This is an important temperature for PMR-15composites because it is the temperature at which the solvent (used tocarry the resin into the fibers) flashes off. The workpiece is allowedto soak at this temperature until the solvent is gone. The operator thenopens the cooler dies 70 and 76 by retracting the press platen 22. Theleft support arm 64 is moved horizontally to the left by extending rod78 in order to move cooler dies 70 and 76 to the left and away from theworkpiece.

The next step is to subject the workpiece to the hotter dies 48 and 50which have been pre-heated to a higher temperature of about 560°-580° F.which is the peak cure temperature for PMR-15 composite. The operatormoves right support arm 58 to the left by activating cylinder 74 toretract rod 72 in order to position the hotter dies 48 and 50 asindicated in FIG. 5. The hotter dies 48 and 50 are then forced down bylowering press platen 22 until the hotter dies 48 and 50 are fullyclosed as shown in FIGS. 6 and 10. At this point, the workpiece 46 isbeing compression molded and cured at about 560°-580° F. The workpieceis held at this temperature for 30 minutes or more for curing.

The next step is to retract the press platen 22 and move right supportarm 58 to the right by extending rod 72 in order to move hotter dies 48and 50 to the right and away from the workpiece. The foregoingprocessing may also be accomplished automatically by using programmablecontrols.

The operator then unloads the finished workpiece 52 from suspension tray44. The process is then repeated on another raw workpiece as describedabove.

As another example, if the raw workpiece 46 is made of thecommercially-available thermoformable plastic material known as TORLONsold by Amoco Chemicals Co., then the cooler dies 70 and 76 should beheated to an intermediate temperature of about 430° F. and the hotterdies 48 and 50 should be heated to a higher temperature of about700°-750° F. TORLON is a polyamideimide material and it is sometimesconsidered to be a thermoplastic material, but for purposes of thepresent invention it is processed in a manner which is similar to theprocess described above for thermosetting materials.

As a further example, if the raw workpiece 46 is made of thecommercially-available thermoformable plastic materials known as theAVIMID K series, such as AVIMID K-III, sold by E. I. du Pont de Nemoursand Co., then the cooler dies 70 and 76 should be heated to anintermediate temperature and the hotter dies 48 and 50 should be heatedto a higher temperature. The AVIMID K series are polyimide materials andare similar to a thermoplastic material after they have beenconsolidated, but initially when in the prepreg form they are processedin a manner which is similar to the process described above forthermosetting materials. As an AVIMID K series material is heated firstto an intermediate temperature and then to a higher temperature, itundergoes a condensation reaction which completely forms the polymer.The completely formed polymer can then be processed in a manner which issimilar to the process described above for thermoplastic materials.

FIGS. 17 and 18 show another embodiment of a hot/cold press formingapparatus 132. Apparatus 132 is a modified version of apparatus 100(FIGS. 15 and 16) and it has certain components that are the same as inapparatus 100. Components of the two embodiments having like design andconstruction have been given the same reference numerals in thedrawings. In this embodiment, the dies are horizontally stationary andthe suspension tray and workpieces are moved horizontally from one pairof dies to the other pair of dies as shown by arrows 136. To preventuneven loading of the press, it is preferred to have a dummy workpiecemove into position in the unused pair of dies at the same time that thereal workpiece moves into position in the pair of dies being used.

Apparatus 132 is designed to solve a problem involved in forming andshaping workpieces having vertical (right-angle) flanges or side wallssuch as finished workpiece 138 shown in FIG. 19. In forming suchcomponents, the problem arises of maintaining sufficient side pressureto react against the vertical flanges or side walls while the workpieceis cooling down in the cold dies of the forming apparatus.

Apparatus 132 solves this problem by having a flexible head 134, such aseither a hydroform head or a hydropress head, instead of an upper colddie above the workpiece. An example of a hydroform head is shown incross section in FIG. 24 and a hydropress head is shown in cross sectionin FIG. 25. A hydropress head or hydroform head maintains the workpiecein the desired final shape, it seals off the pressure media from above,and it provides side pressure against the vertical flanges or sidewalls. In those flange or side wall areas, the flexible head deforms tothe shape of the lower cold die below as pressure is applied. Thisprovides side pressure to react against the vertical flanges or sidewalls. A flexible head like flexible head 134 may also be employed inlike manner in apparatus 20 (FIGS. 1 and 2) and in apparatus 100 (FIGS.15 and 16).

In FIGS. 17 and 18, upper hot die 140 and flexible head 134 are mountedon the lower face of platen 22. A layer of insulation 102 separatesplaten 22 from die 140 and flexible head 134. Another layer ofinsulation 104 separates die 140 and flexible head 134 from each other.Flexible head 134 is usually at ambient temperature, but may be heatedto the necessary elevated temperature when processing thermosettingmaterials or materials like TORLON and the AVIMID K series.

Lower hot die 144 and lower cold die 146 are mounted on base member 82b.A layer of insulation 106 separates base member 82b from dies 144 and146. Another layer of insulation 108 separates dies 150 and 176 fromeach other.

Located on the front side of apparatus 132 is a first positioning frame148 having a horizontal member 150 and two vertical T-shaped positioningposts 152 and 154. Horizontal member 150 slides back and forth on top ofbase member 82b. Each of the four adjustable suspension arms 116a, 116b,116c, and 116d have one end attached to one of the vertical posts 152 or154 and the other end attached to suspension tray 156. A secondpositioning frame 158 of like design having a horizontal member and twovertical T-shaped positioning posts is located on the rear side ofapparatus 132. Four more adjustable suspension arms of like design haveone end attached to one of the vertical positioning posts of positioningframe 158 and the other end attached to suspension tray 156.

Positioning frame 148 is moved back and forth in a horizontal plane byrod 130 which is connected through a linkage to horizontal member 150.Rod 130 is driven by a conventional double-acting cylinder 129 mountedon the front side of base member 82b. A second cylinder and rodcombination of identical design is mounted on the rear side of basemember 82b to move positioning frame 158 back and forth in a horizontalplane in tandem with positioning frame 148 so that suspension tray 156is maintained in correct alignment with the dies. Alternatively, thecylinders can be mounted on the factory floor or some other non-movingstructure. The positioning frames can also be designed as one piece tiedtogether with cross members, and in that event, one cylinder could beemployed instead of two.

It is preferred that suspension tray 156 have three work stations 164,166, and 168 as shown in FIGS. 17 and 18. However, a suspension trayconsisting of a single work station or two work stations can be employedif desired. In the preferred embodiment as shown in FIG. 18, a realworkpiece 170 is placed on the second work station 166 and dummyworkpieces 172 and 174 are placed in the first and third work stations164 and 168, respectively. In FIG. 18, real workpiece 170 is a flatsheet made of thermoformable material (a raw workpiece). It is shown ina sloping position laid on top of suspension tray 156 at second workstation 166. The dummy workpieces prevent the undesirable situation ofuneven loading of the press. When the real workpiece 170 is beingpressed by either hot dies 140 and 144 or cold die 146 and flexible head134, there is a dummy workpiece of equal thickness being pressed by theother pair of dies.

FIG. 18 also shows that when the press in the open position suspensiontray 156 is held by the suspension arms at a level that gives clearanceabove the highest portions of lower dies 144 and 146 so that suspensiontray 156 can move freely back and forth in a horizontal plane withoutbumping the lower dies. In other respects, the construction andoperation of apparatus 132 is similar to apparatus 100 (FIGS. 15 and 16)described earlier.

FIG. 20 shows, in schematic form, another embodiment of a hot/cold pressforming apparatus 176. Apparatus 176 is a modified version of apparatus100 (FIGS. 15 and 16) and it has certain components that are the same asin apparatus 100. Components of the two embodiments having like designand construction have been given the same reference numerals in thedrawings. In this embodiment, the dies are horizontally stationary andthe suspension tray and workpieces are moved horizontally from one pairof dies to the other pair of dies as shown by arrows 178. To preventuneven loading of the press during the press closing motion shown byarrows 180, it is preferred to have a dummy workpiece move into positionin the unused pair of dies at the same time that the real workpiecemoves into position in the pair of dies being used.

Apparatus 176 is designed for forming and shaping gently contouredcomponents made of thermoformable material. An example of a gentlycontoured component is an airplane fairing. Accordingly, upper hot die182 and lower hot die 184 and upper cold die 186 and lower cold die 188are gently contoured in the shape of the desired final workpiece. Thesuspension tray 190 and the optional cover sheet 192 (shown in phantom)have the same gently contoured shape.

In the preferred configuration, suspension tray 190 is supported andmoved by a positioning frame and actuating mechanism like those shown inFIGS. 15 and 16. As in FIGS. 15 and 16, the positioning frame andactuating mechanism move suspension tray 190 from between hot dies 182and 184 to between cold dies 186 and 188 as shown by left arrow 178.

Like the suspension tray shown in FIGS. 15 and 16, the preferred form ofsuspension tray 190 has three work stations. Only center work station194 which supports real workpiece 196 is shown schematically in FIG. 20.However, a suspension tray consisting of a single work station or twowork stations can be employed if desired.

Optional cover sheet 192 is attached to upper hot die 182 or tosuspension tray 190 in such a way that it is released from upper hot die182 or suspension tray 190 when the press is closed. For example, coversheet 192 can be attached to upper hot die 182 by latches which openwhen the press is closed or cover sheet 192 can be detachably supportedabove suspension tray 190 by springs. Cover sheet 190 then moves acrossto the cold dies with workpiece 196 and suspension tray 190.

Cover sheet 192 in most cases would be reusable. If necessary, coversheet 192 and suspension tray 190 may be made of a ductile material tomake up for any die mismatch or nonuniformity in material thickness. Thecover sheet and suspension tray materials help to slow and/or controlcooling.

FIG. 21 shows, in schematic form, another embodiment of a hot/cold pressforming apparatus 198. Apparatus 198 is a modified version of apparatus176 (FIG. 20). Components of the two embodiments having like design andconstruction have been given the same reference numerals in thedrawings. In this embodiment, the dies are horizontally stationary andthe suspension tray and workpieces are moved horizontally from one pairof dies to the other pair of dies as shown by arrows 200. To preventuneven loading of the press during the press closing motion shown byarrows 202, it is preferred to have a dummy workpiece move into positionin the unused pair of dies at the same time that the real workpiecemoves into position in the pair of dies being used.

Apparatus 198 is designed for forming and shaping gently contouredcomponents made of thermoformable material. Apparatus 198 is differentfrom apparatus 176 (FIG. 20) in that the heating dies (upper hot die 204and lower hot die 206) are flat whereas the cooling dies (upper cold die208 and lower cold die 210) are gently contoured in the shape of thedesired final workpiece. Another difference from apparatus 176 is that,in the forming process carried out by apparatus 198, suspension tray 212and optional cover sheet 214 are formed with workpiece 218.

In the preferred configuration, suspension tray 212 is supported andmoved by a positioning frame and actuating mechanism like those shown inFIGS. 15 and 16. As in FIGS. 15 and 16, the positioning frame andactuating mechanism move suspension tray 212 from between hot dies 204and 206 to between cold dies 208 and 210 as shown by left arrow 200.

Like the suspension tray shown in FIGS. 15 and 16, the preferred form ofsuspension tray 212 has three work stations. Only the center workstation 216 which supports the real workpiece 218 is shown schematicallyin FIG. 21. However, a suspension tray consisting of a single workstation or two work stations can be employed if desired.

An elastomeric (rubber-like) material may be used to make suspensiontray. Such a suspension tray can be reused several times. Using arubber-like material for the suspension tray and for the optional coversheet is beneficial because it makes up for small mismatches in thetooling and applies even pressure to the workpiece. An elastomericmaterial may also be used to make the suspension tray in all of theother embodiments described herein.

Alternatively, a film material such as KAPTON (sold by E. I. du Pont deNemours and Company) or nylon can be used as the suspension tray in allof the embodiments for thermoformable plastic materials described hereinand as the optional cover sheet. The film material can be reused ordiscarded after each workpiece is formed. If the same material is usedfor the cover sheet and for the suspension tray, this is beneficialbecause it helps control cooling by cooling the workpiece equally fromboth sides.

Many aircraft components require conductive metal coatings, layers, orsurface materials such as copper foil, copper mesh, copper knitted wire,aluminum foil, aluminum mesh, or flame spray deposition metal plating.These metal materials are used to dissipate electrical charge buildup,to protect against electromagnetic impulses (EMI shielding), or todiffuse the current of a lightning strike. In all of the embodiments forthermoformable plastic materials described herein, a conductive metalmaterial (such as copper foil, copper mesh, aluminum foil, or aluminummesh) can be used as the suspension tray or laid on top of thesuspension tray and the conductive metal material then becomes moldedintegrally into the workpiece as the workpiece goes through the presscycle. Alternatively, the conductive metal material can be laid on topof the workpiece as a cover sheet and the conductive metal material thenbecomes molded into the workpiece as the workpiece goes through thepress cycle.

Thus, a layer of conductive metal material can be either laid on top ofthe workpiece or the suspension tray or the metal material can be usedas the suspension tray. This method of integrally molding a conductivemetal material into the workpiece can be employed in the embodimentsshown in FIGS. 20 and 21.

FIG. 22 shows, in schematic form, another embodiment of a hot/cold pressforming apparatus 220 for gently contoured components made ofthermoformable material. Apparatus 220 is a modified version ofapparatus 176 shown in FIG. 20 and it has certain components that arethe same as in apparatus 176. Components of the two embodiments havinglike design and construction have been given the same reference numeralsin the drawings. In this embodiment, a thin flexible pressure pad 222 isplaced on the lower face of upper cold die 224. Pressure pad 222 can beconstructed in a variety of ways. It can be a bladder filled with oil,air, or a variety of fluids. Another material developed by UnitedTechnologies Corporation for its THERM-X process is a solid that turnsto fluid and flows relatively easily when placed under pressure. Thismaterial can be used inside a bladder or similar pressure head. In someapplications, a thin piece of elastomeric (rubber-like) material can beemployed as pressure pad 222. Apparatus 220 makes it easy to apply evenpressure to a workpiece. Thus, matched die tooling expenses anddifficulties in achieving proper tolerances to apply even pressure areavoided by this embodiment.

FIG. 23 shows another embodiment of a hot/cold press forming apparatus226 for forming complex-shaped components such as workpiece 228. In thisembodiment, the dies are horizontally stationary and suspension tray 230and workpiece 228 are moved horizontally by shuttle mechanism 232 fromone pair of dies to the other pair of dies as shown by arrows 234. Upperhot die 236 and upper cold die 238 are mounted on the lower face ofpress platen 240. A layer of insulation 242 separates press platen 240from upper hot die 236. Lower hot die 244 and lower cold die 246 aremounted on base member 248. A layer of insulation 250 separates basemember 248 from lower hot die 244.

Shuttle mechanism 232 consists of a first positioning assembly 252having a horizontal member 254 and two vertical cylinders 256 and 258mounted thereon. Cylinders 256 and 258 are spring-loaded so that supportarms 260 and 262 recess into the cylinders as press platen 240 comesdown. Horizontal member 254 slides on track 264 mounted on top of basemember 248. Support arms 260 and 262 have an inverted L-shape. Thehorizontal ends of support arms 260 and 262 fit into the recesses shownin the top of lower hot die 244 and lower cold die 246 when press platen240 is in the closed position.

A second positioning assembly 266 having a horizontal member and twovertical cylinders of like design and construction are located on therear side of apparatus 226. Second positioning assembly 266 moveshorizontally on track 268 in parallel with first positioning assembly252.

FIG. 24 shows, in vertical section, another embodiment of a hot/coldpress forming apparatus 270 for forming complex-shaped components suchas workpiece 272. In this embodiment, the dies are horizontallystationary and suspension tray 274 and workpiece 272 are movedhorizontally by a shuttle mechanism from one pair of dies to the otherpair of dies as shown by arrows 278. A shuttle mechanism having the samedesign and construction as shuttle mechanism 232 shown in FIG. 23 isemployed in apparatus 270 but it is omitted for clarity in FIG. 24. Anoptional cover sheet that may be laid over workpiece 272 has also beenomitted for clarity in FIG. 24.

Upper hot die 280 and upper forming unit 282 are mounted on the lowerface of press platen 284. The press motion is shown by arrows 276. Alayer of insulation 286 separates press platen 284 from upper hot die280. Lower hot die 288 and lower cold die 290 are mounted on base member292. A layer of insulation 294 separates base member 292 from lower hotdie 288.

In apparatus 270, upper forming unit 282 is a hydroform head. Thehydroform head consists of a chamber 296 into which a fluid (such asoil) is pumped under pressure through line 298 when press platen 284 isin the closed position. The side walls of chamber 296 contain the fluidand force it against flexible bladder 300 which expands againstworkpiece 272. The fluid can be heated to the necessary elevatedtemperature when processing thermosetting materials or materials likeTORLON. Workpiece 272 is pressed against suspension tray 274 which ispressed against tool 302 in the center of lower cold die 290. Ifdesired, tool 302 can be pushed vertically by optional ram cylinder 304.

If desired, a pair of flat heating dies like the flat heating dies 204and 206 in apparatus 198 (FIG. 21) can be employed in apparatus 270.

FIG. 25 shows, in vertical section, another embodiment of a hot/coldpress forming apparatus 306 for forming complex-shaped components suchas workpiece 308. In this embodiment, the dies are horizontallystationary and suspension tray 310 and workpiece 308 are movedhorizontally by a shuttle mechanism from one pair of dies to the otherpair of dies as shown by arrows 312. A shuttle mechanism having the samedesign and construction as shuttle mechanism 232 shown in FIG. 23 isemployed in apparatus 306 but it is omitted for clarity in FIG. 25. Anoptional cover sheet that may be laid over workpiece 308 has also beenomitted for clarity in FIG. 25.

Upper hot die 314 and upper forming unit 316 are mounted on the lowerface of press platen 318. The press motion is shown by arrows 319. Alayer of insulation 320 separates press platen 318 from upper hot die314. Lower hot die 322 and lower cold die 324 are mounted on base member326. A layer of insulation 328 separates base member 326 from lower hotdie 322.

In apparatus 306, upper forming unit 316 is a hydropress head. Thehydropress head consists of a chamber 330 which is filled with anelastomeric (rubber-like) material 322. The side walls of chamber 330contain elastomeric material 332 and force it against workpiece 308.Workpiece 308 is pressed against suspension tray 310 which is pressedagainst tool 334 in the center of lower cold die 324.

If desired, a pair of flat heating dies like the flat heating dies 204and 206 in apparatus 198 (FIG. 21) can be employed in apparatus 306.

FIG. 26 shows, in vertical section, another embodiment of a hot/coldpress forming apparatus 336 for forming complex-shaped components suchas workpiece 338. In this embodiment, the dies are horizontallystationary and suspension tray 340 and workpiece 338 are movedhorizontally by a shuttle mechanism from one pair of dies to the otherpair of dies as shown by arrows 344. A shuttle mechanism having the samedesign and construction as shuttle mechanism 232 shown in FIG. 23 isemployed in apparatus 336 but it is omitted for clarity in FIG. 26. Anoptional cover sheet that may be laid over workpiece 338 also has beenomitted from FIG. 26 for clarity.

Upper hot die 346 and upper forming unit 348 are mounted on the lowerface of press platen 350. The press motion is shown by arrows 342. Alayer of insulation 352 separates press platen 350 from upper hot die346. Lower hot die 354 and lower cold die 356 are mounted on base member358. A layer of insulation 360 separates base member 358 from lower hotdie 354.

In apparatus 336, upper forming unit 348 is a modified hydropress head.The modified hydropress head consists of a chamber 362 which is filledwith an elastomeric (rubber-like) material 364 which is machined or castwith a recessed portion 366 in the desired shape of the final component.The side walls of chamber 362 contain elastomeric material 364 and forceit against workpiece 338. Workpiece 338 is pressed against suspensiontray 340 which is pressed against tool 368 in the center of lower colddie 356.

If desired, a pair of flat heating dies like the flat heating dies 204and 206 in apparatus 198 (FIG. 21) can be employed in apparatus 336. Acover sheet may also be used with the flat heating dies.

As will be apparent to those skilled in the art to which the inventionis addressed, the present invention may be embodied in forms other thanthose specifically disclosed above, without departing from the spirit oressential characteristics of the invention. The particular embodimentsof apparatus described above and the particular details of the processesdescribed are therefore to be considered in all respects as illustrativeand not restrictive. The scope of the present invention is as set forthin the appended claims rather than being limited to the examples ofapparatus and processes set forth in the foregoing description. Any andall equivalents are intended to be embraced by the claims.

What is claimed is:
 1. A method of forming and shaping a workpiece madeof thermoformable material using a first pair of forming means at afirst temperature and a second pair of forming means at a secondtemperature, which comprise the steps of:(a) providing a tray meanssuspended in midair by suspension means; (b) loading said workpiece madeof thermoformable material on said tray means suspended in midair; (c)moving said first pair of forming means horizontally into position abovesaid workpiece and below said tray means; (d) closing said first pair offorming mean against said workpiece and said tray means to heat saidworkpiece and to form and shape said workpiece into a formed workpieceof desired configuration; (e) opening said first pair of forming meansand moving said first pair of forming means horizontally away from saidformed workpiece and said tray means; (f) moving said second pair offorming means horizontally into position above said formed workpiece andbelow said tray means; (g) closing said second pair of forming meansagainst said formed workpiece and said tray means to cool said formedworkpiece while maintaining said formed workpiece in the desiredconfiguration; and (h) opening said second pair of forming means andunloading said formed and cooled workpiece.
 2. The method of claim 1wherein the thermoformable material is a thermoplastic material.
 3. Themethod of claim 2 wherein the thermoplastic material is selected fromthe group consisting of polyetheretherketone, polyphenylene sulfide,polyetherimide, polyamideimide, polyethersulfone, polyimide, andpolypropylene.
 4. The method of claim 1 wherein the thermoformablematerial is a thermosetting material.
 5. The method of claim 1 whereinthe thermoformable material is a metal material.
 6. The method of claim1 wherein the first pair of forming means is at a temperature of about750° F. and the second pair of forming means is at a temperature belowabout 290° F.
 7. The method of claim 1 wherein the first pair of formingmeans is at a temperature of about 650° F. and the second pair offorming means is at a temperature below about 180° F.
 8. The method ofclaim 1 wherein a cover sheet is placed on top of the workpiece.
 9. Themethod of claim 1 wherein one of the forming means of the second pair offorming means is a flexible head means.
 10. The method of claim 9wherein the flexible head means is selected from the group consisting ofa hydroform head, a hydropress head, and a modified hydropress head. 11.The method of claim 1 wherein the tray means is made of an elastomericmaterial.
 12. The method of claim 1 wherein the tray means is made of afilm material.
 13. The method of claim 1 wherein a conductive metalmaterial is used either as the tray means or as a cover sheet laid ontop of the tray means, and the conductive metal material becomes moldedinto the workpiece
 14. The method of claim 1 wherein a conductive metalmaterial is used as a cover sheet laid on top of the workpiece and theconductive metal material becomes molded into the workpiece.
 15. Amethod of forming and shaping a workpiece made of thermoformablematerial using a first pair of forming means at a first temperature anda second pair of forming means at a second temperature, which comprisesthe steps of:(a) providing a tray means suspended in midair bysuspension means; (b) loading said workpiece made of thermoformablematerial on said tray means suspended in midair; (c) moving saidworkpiece and said tray means into position between said first pair offorming means; (d) closing said first pair of forming means against saidworkpiece and said tray means to heat said workpiece and to form andshape said workpiece into a formed workpiece of desired configuration;(e) opening said first pair of forming means and moving said formedworkpiece and said tray means away from said first pair of formingmeans; (f) moving said formed workpiece and said tray means intoposition between said second pair of forming means; (g) closing saidsecond pair of forming means against said formed workpiece and said traymeans to cool said formed workpiece while maintaining said formedworkpiece in the desired configuration; and (h) opening said second pairof forming means and unloading said formed and cooled workpiece.
 16. Themethod of claim 15 wherein the thermoformable material is athermoplastic material.
 17. The method of claim 16 wherein thethermoplastic material is selected from the group consisting ofpolyetheretherketone, polyphenylene sulfide, polyetherimide,polyamideimide, polyethersulfone, polyimide, and polypropylene.
 18. Themethod of claim 15 wherein the first pair of forming means is at atemperature of about 750° F. and the second pair of forming means is ata temperature below of about 290° F.
 19. The method of claim 15 whereinthe first pair of forming means is at a temperature of about 650° F. andthe second pair of forming means is at a temperature below about 180° F.20. The method of claim 15 wherein a cover sheet is placed on top of theworkpiece.
 21. The method of claim 15 wherein one of the forming meansof the second pair of forming means is a flexible head means.
 22. Themethod of claim 21 wherein the flexible head means is selected from thegroup consisting of a hydroform head, a hydropress head, and a modifiedhydropress head.
 23. The method of claim 15 wherein the tray means has aplurality of work stations with a real workpiece supported at one of thework stations and with dummy workpieces supported at the other workstations.
 24. The method of claim 15 wherein the tray means is made ofan elastomeric material.
 25. The method of claim 15 wherein the traymeans is made of a film material.
 26. The method of claim 15 wherein aconductive metal material is used either as the tray means or as a coversheet laid on top of the tray means, and the conductive metal materialbecomes molded into the workpiece.
 27. The method of claim 15 wherein aconductive metal material is used as a cover sheet laid on top of theworkpiece and the conductive metal material becomes molded into theworkpiece.
 28. The method of claim 15 wherein one of the forming meansof the second pair of forming means includes a flexible pressure padplaced on the face of the forming means.
 29. The method of claim 15wherein one of the forming means of the second pair of forming meansincludes a tool which is moved by a ram cylinder.
 30. A method ofproducing a finished workpiece by forming and shaping a workpiece madeof thermoformable plastic material using a first pair of forming meansat a first temperature and a second pair of forming means at a secondtemperature, which comprises the steps of:(a) providing a tray meanssuspended in midair by suspension means; (b) loading and workpiece madeof thermoformable plastic material on said tray means suspended inmidair; (c) moving said first pair of forming means horizontally intoposition above said workpiece and below tray means; (d) closing saidfirst pair of forming means against said workpiece and said tray meansto heat said workpiece to an intermediate temperature and to form andshape said workpiece into a formed workpiece of desired configuration;(e) opening said first pair of forming means and moving said first pairof forming means horizontally away from said formed workpiece and saidtray means; (f) moving said second pair of forming means horizontallyinto position above said formed workpiece and below said tray means; (g)closing said second pair of forming means against said formed workpieceand said tray means to heat said formed workpiece to a highertemperature while maintaining the formed workpiece in the desiredconfiguration thereby forming said finished workpiece; and (h) openingsaid second pair of forming means and unloading said finished workpiece.31. The method of claim 30 wherein the thermoformable plastic materialis a thermosetting material.
 32. The method of claim 30 wherein thethermoformable plastic material contains polyimide.
 33. The method ofclaim 30 wherein the thermoformable plastic material containspolyamideimide.
 34. The method of claim 30 wherein the first pair offorming means is at a temperature of about 430° F. and the second pairof forming means is at a temperature of about 560°-580° F.
 35. Themethod of claim 30 wherein the first pair of forming means is at atemperature of about 430° F. and the second pair of forming means is ata temperature of about 700°-750° F.
 36. The method of claim 30 wherein acover sheet is placed on top of the workpiece.
 37. The method of claim30 wherein one of the forming means of the second pair of forming meansis a flexible head means.
 38. The method of claim 37 wherein theflexible head means is selected from the group consisting of a hydroformhead, a hydropress head, and a modified hydropress head.
 39. The methodof claim 30 wherein the tray means is made of an elastomeric material.40. The method of claim 30 wherein the tray means is made of a filmmaterial.
 41. The method of claim 30 wherein a conductive metal materialis used either as the tray means or as a cover sheet laid on top of thetray means, and the conductive metal material becomes molded into theworkpiece.
 42. The method of claim 30 wherein a conductive metalmaterial is used as a cover sheet laid on top of the workpiece and theconductive metal material becomes molded into the workpiece.
 43. Amethod of producing a finished workpiece by forming and shaping aworkpiece made of thermoformable plastic material using a first pair offorming means at a first temperature and a second pair of forming meansat a second temperature, which comprises the steps of:(a) providing atray means suspended in midair by suspension means; (b) loading saidworkpiece made of thermoformable plastic material on said tray meanssuspended in midair; (c) moving said workpiece and said tray means intoposition between said first pair of forming means; (d) closing saidfirst pair of forming means against said workpiece and said tray meansto heat said workpiece to an intermediate temperature and to form andshape said workpiece into a formed workpiece of desired configuration;(e) opening said first pair of forming means and moving said formedworkpiece and said tray means away from said first pair of formingmeans; (f) moving said formed workpiece and said tray means intoposition between said second pair of forming means; (g) closing saidsecond pair of forming means against said formed workpiece and said traymeans to heat said formed workpiece to a higher temperature whilemaintaining said formed workpiece in the desired configuration therebyforming said finished workpiece; and (h) opening said second pair offorming means and unloading said finished workpiece.
 44. The method ofclaim 43 wherein the thermoformable plastic material is a thermosettingmaterial.
 45. The method of claim 43 wherein the thermoformable plasticmaterial contains polyimide.
 46. The method of claim 43 wherein thethermoformable plastic material contains polyamideimide.
 47. The methodof claim 43 wherein the first pair of forming means is at a temperatureof about 430° F. and the second pair of forming means is at atemperature of about 560°-580° F.
 48. The method of claim 43 wherein thefirst pair of forming means is at a temperature of about 430° F. and thesecond pair of forming means is at a temperature of about 700°-750° F.49. The method of claim 43 wherein a cover sheet is placed on top of theworkpiece.
 50. The method of claim 43 wherein one of the forming meansof the second pair of forming means is a flexible head means.
 51. Themethod of claim 50 wherein the flexible head means is selected from thegroup consisting of a hydroform head, a hydropress head, and a modifiedhydropress head.
 52. The method of claim 43 wherein the tray means ismade of an elastomeric material.
 53. The method of claim 43 wherein thetray means is made of a film material.
 54. The method of claim 43wherein a conductive metal material is used either as the tray means oras a cover sheet laid on top of the tray means, and the conductive metalmaterial becomes molded into the workpiece.
 55. The method of claim 43wherein a conductive metal material is used as a cover sheet laid on topof the workpiece and the conductive metal material becomes molded intothe workpiece.